DOI: 10.3303/CET25120086 Paper Received: 14/04/2025; Revised: 25 August 2025; Accepted: 28 September 2025 Please cite this article as: Bian R., He R., Yan X., Tong X., 2025, LSTM-Driven Predictive Scheduling for Green Energy-Hydrogen-Methanol Integrated System, Chemical Engineering Transactions, 120, 511-516 DOI:10.3303/CET25120086 CHEMICAL ENGINEERING TRANSACTIONS VOL. 120, 2025 A publication of The Italian Association of Chemical Engineering Online at www.cetjournal.it Guest Editors: Bing Shen How, Viknesh Andiappan, Denny K.S. Ng, Hon Loong Lam, Petar S. Varbanov Copyright © 2025, AIDIC Servizi S.r.l. ISBN 979-12-81206-21-2; ISSN 2283-9216 LSTM-Driven Predictive Scheduling for Green Energy- Hydrogen-Methanol Integrated System Rui Biana, Renchu Hea,*, Xinyu Yana, Xinglin Tongb aDepartment of Automation, College of Artificial Intelligence, China University of Petroleum, Beijing, 102249, China bWuhan University of Technology, Wuhan, 430070, China rche@cup.edu.cn This study proposes an optimization scheduling model for the Green Energy-Hydrogen-Methanol Integrated System (GEHMIS) based on the Long Short-Term Memory (LSTM) network, aimed at achieving efficient, stable, and economical operation of renewable energy systems. In response to the fluctuations and uncertainties in the output of wind and solar energy, this paper introduces the LSTM network to accurately predict wind speed and temperature using historical data. The integrated system model developed in this study covers key processes such as wind and solar power generation, water electrolysis for hydrogen production, hydrogen storage and transportation, and methanol synthesis. The objective of this research is to maximize the overall system profit by developing a multi-constraint mathematical optimization model that takes into account multiple factors, including hydrogen and methanol production efficiencies, hydrogen consumption, operation and maintenance costs, electricity price fluctuations, grid interactions, and carbon dioxide costs. Compared to traditional random resource allocation strategies, the proposed optimization model demonstrates significant advantages in terms of economic benefits and energy utilization efficiency: the overall system profit increased by approximately 68.3 %, and the hydrogen utilization rate improved by 30 %. This provides important technical support and a practical pathway for the large-scale application of green energy and the global transition to sustainable energy. 1. Introduction Amid growing global energy crisis and environmental challenges, the over-reliance on traditional energy sources has created pressing issues, necessitating urgent development of clean and sustainable energy solutions (Wang et al., 2023). While renewable energies like wind and solar power face integration and storage challenges in large-scale applications, hydrogen and methanol have emerged as promising clean energy carriers (Mazzeo et al., 2022). The wind-solar hydrogen-to-methanol technology not only enhances renewable energy utilization but also contributes to CO₂ reduction, offering significant environmental advantages. However, the intermittent nature of wind and solar power complicates accurate forecasting and scheduling using conventional methods. Long Short-Term Memory (LSTM) networks, a specialized Recurrent Neural Network (RNN) architecture introduced by Hochreiter and Schmidhuber (1997) in 1997, demonstrated exceptional capability in capturing long-term dependencies and have been widely adopted for renewable energy forecasting (Sherstinsky, 2020). Al-qaness et al. (2024) achieved improved wind power prediction accuracy by integrating LSTM with optimization algorithms. In the context of energy economic efficiency, the concept of the methanol economy proposed by Prakash et al. (2011) regarded the hydrogenation of CO₂ to methanol as one of the most attractive and potentially profitable technological pathways. To realize the systematic application of this pathway, Macedo and Peyerl (2022) conducted an economic analysis of hydrogen production from wind-solar power plants in Brazil, demonstrating that selling hydrogen is more economically beneficial than converting it into electricity. Zheng et al. (2022) constructed a model of the production system and quantitatively evaluated the influence of key operational parameters on methanol cost structures. Currently, most wind and solar power generation methods still rely on static or low-accuracy weather forecasting models, which struggle to capture the dynamic nature of renewable energy. Although some studies have explored green electricity-based hydrogen production pathways, few have addressed specific strategies for equipment scheduling and hydrogen processing. Moreover, existing research mainly focuses on hydrogen itself, 511 lacking comprehensive analysis of co-production with downstream products, such as methanol, and related market revenues, resulting in limited model practicality and incomplete assessment of system-level economic performance. To address these issues, this paper proposes an LSTM-based optimization method for scheduling in GEHMIS. The LSTM network, trained on historical data, is used to predict wind speed and temperature, enabling dynamic, multi-constraint optimization of hydrogen production and methanol synthesis. The model aims to maximize overall profit by optimizing power allocation and ensuring stable and efficient system operation. This approach offers the potential for cost reduction, emission mitigation, and improved economic performance, providing both theoretical and practical value. 2. Modeling methodology for the GEHMIS The GEHMIS primarily comprises the wind-solar power generation system, hydrogen production by electrolyzer, grid interaction, and methanol production and sales. Hydrogen is partly sold and partly used with CO₂ to produce methanol. Renewable power is prioritized for electrolyzer, with surplus sold; when insufficient, grid electricity is purchased to maintain stable operation. The specific schematic diagram is shown in Figure 1. Photovoltaic Power Generation Wind Power Generation Electrolyzer Methanol Production Methanol Sales Power Grid CO2 Electric Power Flow Hydrogen Flow CO2 Flow Methanol Flow Hydrogen Sales Figure 1: The structural diagram of the GEHMIS 2.1 System mathematical models The study establishes a a wind–solar–hydrogen–methanol model and enables interaction with the power grid. (1) Wind power model 1 3 2 3 , 1 2 0 2 3 0 1 2 WD t P v v or v v P R C v v v v P v v v      =       (1) Eq(1) represents the wind power model based on the works of Wang et al. (2024). The output power of the wind turbine ,WD tP over a time period t is jointly determined by the radius of the turbine blades R, wind energy utilization coefficient PC , wind speed v, and the rated power 0P . 1 2 3, ,v v v represent the cut-in wind speed, rated wind speed and cut-out wind speed of the wind turbine, respectively. (2) Photovoltaic power model =  + −  , [1 ( 25)]PV t STC t PV PVP P k T S (2) The photovoltaic power model in Eq(2) is derived from the methodology proposed by Yousefi et al. (2017), where, ,PV tP denotes the photovoltaic power output and tT represents surface temperature. STCP represents the light intensity coefficient, k is the power temperature coefficient, PV is the conversion efficiency of the photovoltaic array, and PVS is the area of the photovoltaic array. (3) Electrolyzer and methanol synthesis section models Eq(3) and Eq(4) formulate the electrolyzer and methanol synthesis section models based on the works of Buttler and Spliethoff (2018). 512  =   =  2 4 4 4 2 4 ,H CH CH CHE PEM t t H t t CHq P L q P L (3)  =  =4 4 2 4 2, /CH CH CO CH COCHH t t t tq q q V (4) where, 2 4, HH t C t qq represent the hydrogen and methanol production,   4, CHE represent the production efficiency of hydrogen and methanol, 4, CHPEM t tP P represent the power consumption of the electrolyzer and the methanol production equipment, and 2 4 ,H CHL L represent the electricity-to-hydrogen and electricity-to-methanol factor. CHH tq refers to the hydrogen required for methanol production, while  4CH refers to the hydrogen consumption per kg of methanol produced. 2CO tq is the required production of CO2, and  2CO refers to the carbon dioxide utilization rate. 2.2 System optimization models This study focuses on short-term scheduling issues. Since the initial investment cost is a fixed expenditure, it is not considered. This study also disregards system start-up/shutdown costs and separate transportation costs. 2 max revenu inve M COC C C C C= − − − (5) where, Eq(5) is the objective function of the model. C represents the total revenue, revenueC includes the sales of hydrogen and methanol, while invC represents the operating costs, MC is the grid interaction costs, and 2COC represents the cost of CO2. (1) Revenue calculation = =  +  2 _2 4 4 t t 1 ( )sell revenue T HH CH CH t C c q c V (6) where, 2Hc and 4CHc represent the market selling prices of hydrogen and methanol, and 2 _H sell t q represents the quantity sold of hydrogen. (2) Cost calculation  = = =   4 1 1 ( ( )) T t inv i i t i C c (7)   = =  −  1 ( ) T buy sell M buy t sell t t C P P (8)  = =  2 2 2 1 )( CO t T CO CO t qC (9) where, i represents the various system equipment, including wind power generation, photovoltaic generation, electrolyzer, and methanol production units. ic represent the operating costs of each type of equipment, and  t i represent the consumption of each equipment. ,buy sell  and  2CO represent purchasing, selling price of the electricity, and carbon dioxide purchasing price. ,buy sell t tP P represent the power associated with buying and selling electricity, respectively. The model constraint equations are as follows: (1) Power constraint + + = + + 4 , , CHbuy sell PEM WD t PV t t t t tP P P P P P (10) The total of generated and purchased electricity equals the sum of electricity consumption and electricity sold. (2) Hydrogen balance constraint + =2 2 4 2_ ,H sell H CH H t t tq q q (11) 513 The hydrogen produced by the electrolyzer 2H tq is supplied for methanol production 2 4,H CH tq and sold for hydrogen use 2 _H sell tq . (3) Interaction and power constraints min maxPEM PEM t PEMP P P  (12)  4 4 4 min maxCH CH t CHP P P (13)          −  min max , min max ,(1 ) buy M t M t M sell M t M t M P P P P P P (14) where, 4 4 min max min max min max, , , , ,PEM PEM CH CH M MP P P P P P are the minimum and maximum power of the electrolyzer, methanol production equipment, and grid interaction.  ,M t represents the state of purchasing and selling electricity from the superior power grid, where a value of 1 indicates purchase mode and 0 indicates sale mode. 3. Case study and system parameters This case study selects Cangzhou, Hebei Province, China, as the target region. Based on wind speed and temperature data predicted by the LSTM neural network model, a dynamic optimization scheduling analysis of the GEHMIS was conducted over a two-month period, using a one-day time step. The key components involved in the system include wind turbine, photovoltaic module, electrolyzer, and methanol synthesis unit, with their core unit costs in Table 1 (Wiser et al., 2019). In terms of economic parameters, the selling price of methanol is set at 2.6 CNY/kg, the cost of CO₂ capture is 0.40 CNY/kg, and the hydrogen selling price is 20 CNY/kg (Liu et al., 2023). Meanwhile, the system is connected to the main power grid, with average electricity purchase price of 0.3 CNY/kWh and selling price of 0.15 CNY/kWh (Yang et al., 2023). Table 1: Costs of each equipment Equipment Operating cost Wind turbine 0.04 CNY/kWh Photovoltaic 0.05 CNY/kWh Electrolytic cell 0.2 CNY/kWh Methanol production equipment 0.528 CNY/kg 4. Analysis of system results This section primarily focuses on conducting an in-depth analysis of the LSTM prediction results and the system optimization scheduling results obtained by using the CPLEX optimizer based on the parameter settings. 4.1 LSTM-based prediction results To evaluate the forecasting accuracy of the LSTM model, the prediction performance and error trends are analyzed to evaluate the method’s reliability. The results are shown in Figure 2. Figure 2(a) presents a comparison between the actual and LSTM-predicted wind speed values, with the prediction errors ranging from -0.036 to 0.020. Figure 2(b) depicts temperature prediction results, where the errors between predicted and actual values range from -0.094 to 0.131. a b Figure 2: Prediction results of (a) LSTM wind speed, (b) temperature 514 These error values denote the point-wise deviation between predicted and actual values, expressed in the same units as the target variables. The mean absolute percentage error (MAPE) was introduced to systematically evaluate overall model performance, where lower values indicate higher predictive accuracy. It is defined as: = − =  1 ˆ1 | | 100% n i i i i y y MAPE n y (15) where, iy denotes the actual observed value, ˆ iy represents the predicted value, and n is the total number of samples. Both MAPE value of wind speed and temperature predictions are below 0.3 %, demonstrating the model's exceptionally strong forecasting accuracy. 4.2 Optimized scheduling results of the GEHMIS The optimized system operation is analyzed, including equipment scheduling and power transactions, in accordance with energy and hydrogen balance principles. Figure 3(a) illustrates the overall power balance scheduling, where wind and photovoltaic systems generate a total of 1.423×105 kWh during the cycle. Figure 3(b) presents the hydrogen scheduling balance, where the electrolyzer produces 5.877×104 kg of hydrogen, of which 3.996×104 kg is sold. The remaining hydrogen is used for methanol synthesis, yielding 1.8076×104 kg of methanol. The overall hydrogen utilization rate is approximately 32 %. a b Figure 3: (a) Electrical power, (b) hydrogen balance scheduling diagram of the optimized model a b Figure 4: (a) Electrical power, (b) hydrogen balance scheduling diagram of the stochastic model ba Figure 5: The revenue and cost of the (a) optimized model, (b) stochastic model According to Figure 5(a), the total system revenue amounts to 9.86×105 CNY. Among this, hydrogen sales are the primary source of income, generating 7.995×105 CNY, which accounts for approximately 81 % of the total revenue. The final system profit is 1.237×105 CNY. To further validate the advantages of the optimized scheduling model, a comparative analysis was conducted against a stochastic model under the same cost parameters. As shown in Figure 4(b), the electrolyzer produces a total of 9.936×104 kg of hydrogen, of which 515 only 2 % is used for methanol synthesis. Figure 5(b) shows that the stochastic model yields a final profit of 7.348×104 CNY, while the optimized model achieves a 68.3 % increase in profit. In addition, the hydrogen utilization rate rises from 2 % to 32 %, indicating a higher share of hydrogen being used for methanol production. These results demonstrate that, under all operational constraints, the optimized scheduling model significantly enhances the economic performance and energy conversion efficiency. 5. Conclusions Experimental research on the GEHMIS based on LSTM prediction demonstrates excellent performance in wind speed and temperature prediction, with MAPE below 0.3 %. Compared to the random allocation model, the optimized scheduling model boosts economic benefits by 68.3 %, increases hydrogen utilization rate by 30 %. These results demonstrate that the optimized model significantly improves system operational efficiency and economic performance, providing strong support for stable operation and efficient energy conversion. Future research should focus on integrating multi-objective optimization algorithms and improving real-time scheduling to enhance system performance. These advances will support large-scale green energy deployment and aid the global energy transition toward sustainable development goals. Acknowledgments This work was supported by National Natural Science Foundation of China (62073142), Science Foundation of China University of Petroleum, Beijing (No.2462024YJRC011) and the Open Research Project of the State Key Laboratory of Industrial Control Technology, China (Grant No. ICT2024B70). Xinglin Tong is an adjunct professor at the Department of Automation, College of Artificial Intelligence, China University of Petroleum, Beijing. 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Energy Conversion and Management, 256, 115338. 516 0252.pdf LSTM-Driven Predictive Scheduling for Green Energy-Hydrogen-Methanol Integrated System